KEF LS50 and Sub Optimization?

[Mehdiem]

I have been experimenting with my LS50 and Sub KEF Q400 for several years, and still cannot find the optimal sweet spot for crossover and sub volume. The issue is that I find a good setting based on one song and album (let's say Diana Krall - Wonderful) but later when I listen to another album on a different genre (soundtrack, classical, etc) everything sounds bad. In the past, I set the crossover between 60-70 but recently saw a few people in this forum talking about 100!
Please share your perspective.

My equipments are the following:
- Node Streamer
- RME ADI-2 DAC, Preamp
- Yamaha NR-602 amp (waiting for my NAD C298 to arrive in couple of weeks)
- just bought UMIK but a newbie to REW and measurement

 

[abdo123]

Seal the port with socks and put the crossover on ~95Hz. Adjust volume to preference.

 

[Mehdiem]

Seal the port with socks and put the crossover on ~95Hz. Adjust volume to preference.

Do you mean LS50 port? I have filled them with original foam provided by KEF. As for sub, there is no port on my sub. Is that what you meant?

What about the EQ at the back of SuB? +6db is ok? Or should do differnetly?

 

[abdo123]

I don’t know how the EQ controls for your particular sub is, but the optimal crossover for the LS50 should be at 95Hz with the ports sealed.

 

[Mehdiem]

I don’t know how the EQ controls for your particular sub is, but the optimal crossover the LS50 should be at 95Hz with the ports sealed.

I set it around it and it started sounding much different and better!

 

[abdo123]

Btw the node streamer has an option to apply high-pass / crossover to both the speakers and the subwoofer if you use its analogue output + subwoofer output.

it's an interesting option to consider since you don't really have a digital signal processor at the moment and the LS50 is still being given a full range signal.

Always make sure to defeat the crossover in the subwoofer (read the manual, this is usually the case when you use the LFE input of some subwoofers) if you're going to use a crossover somewhere else.

 

[Mehdiem]

Btw the node streamer has an option to apply high-pass / crossover to both the speakers and the subwoofer if you use its analogue output + subwoofer output.

it's an interesting option to consider since you don't really have a digital signal processor at the moment and the LS50 is still being given a full range signal.

Always make sure to defeat the crossover in the subwoofer (read the manual, this is usually the case when you use the LFE input of some subwoofers) if you're going to use a crossover somewhere else.

I'm using Node Optical Out to RME. I might be able to do something similar with RME. I guess I might be able to set different EQs for XLR and RCA out. Then I can connect the SUB to RCA out, and the new amp to XLR. But I don't know if I can set the separate crossover on RME.

 

[More Dynamics Please]

I've been known to change my crossover setting when listening to different recordings with significantly different bass balance. The issue is not with our audio systems but with the recording chain as described on Sean Olive's blog as audio's circle of confusion, a term coined by Floyd Toole:

Audio's Circle of Confusion

Audio’s “Circle of Confusion” is a term coined by Floyd Toole [1] that describes the confusion that exists within the audio recording and r...

seanolive.blogspot.com

 

[Slick Minkus]

Sounds like a placement issue, with different recordings exposing/exaggerating peaks and nulls in your room.
EQ and crossover points may help (specifically with peaks), but will unlikely provide the solution you need.
The following SVS blog-post is an easy read on the topic that i'm sure someone else here can elaborate on further. Hopefully with some good guidance for your newly acquired UMIK as measurements are your best bet...

The Art of Subwoofer Placement (SVS)

 

[pablolie]

It's always going to be a compromise - even without a sub some recording will sound more "real" that others when you optimize your system for those.

I do xover at 70Hz with the LS50... room friendly positioning and setup is key. Unless you turn up the volume way high (and then why would you get bookshelves anyhow), that is a pretty agreed upon sweet spot.

Also keep in mind some tracks will accentuate that 60-250Hz region more than others, so they'll come across very differently.

 

[abdo123]

Using the crossover to 'EQ' the system is really amateurish to be honest. specially when the volume knob is right next to the crossover knob.

 

[pablolie]

Using the crossover to 'EQ' the system is really amateurish to be honest. specially when the volume knob is right next to the crossover knob.

Uh? Explain what you mean. My amp controls crossover points. Room optimization SW too. What magic and superior tool do you use?

 

[abdo123]

Uh? Explain what you mean. My amp controls crossover points. Room optimization SW too. What magic and superior tool do you use?

Parametric EQ.

 

[pablolie]

Parametric EQ.

Fully parametric is overkill. Every EQ is parametric by definition, by the way, the question is the degree of it.

 

[Mehdiem]

Parametric EQ.

1- Should I keep the sub on at 100 crossover and set the volume to my preferred level, before performing the room measurement? Or after?
2- Should I perform room measurement with speakers and sub on at the same time, or should I do them separately?

 

[Ron Texas]

I use 100 hz crossover 4th order slopes both ways.

 

[phoenixdogfan]

I also use 100 hz LR with a single SB2000 for my Metas.

 

[Mowz]

No crossover for moderate listening levels, just eq. I only cross over when listening above 85db since no real distortion to worry about until then, better room modes with multiples sources etc.

Crossed over at 95 for high volume when I had one sub.

Now i low pass at 150 for high volume (i think. I can confirm if anyone cares) , but now I have 3subs. Messed with this for months, haven't changed it in a month.

Also this is my first post though I have lived on these forums for the past several months ever since I read a post on what hifi capping on you guys. I've learned so much!

 

[aarons915]

I have been experimenting with my LS50 and Sub KEF Q400 for several years, and still cannot find the optimal sweet spot for crossover and sub volume. The issue is that I find a good setting based on one song and album (let's say Diana Krall - Wonderful) but later when I listen to another album on a different genre (soundtrack, classical, etc) everything sounds bad. In the past, I set the crossover between 60-70 but recently saw a few people in this forum talking about 100!
Please share your perspective.

My equipments are the following:
- Node Streamer
- RME ADI-2 DAC, Preamp
- Yamaha NR-602 amp (waiting for my NAD C298 to arrive in couple of weeks)
- just bought UMIK but a newbie to REW and measurement

I'm not familiar with your gear but I've had the same issues for years and the LS50 are a bit harder than most to blend with subs because they want higher crossover frequencies to combat distortion but then you're fighting with a proper blend and subwoofer localization. I've always had dual subs with mine right under the LS50's, using a single sub will be harder to get it right but it's doable. Your Umik and REW will be the best investment you made in your system once you figure out how to take accurate and repeatable measurements, google MMM measurements. Sometimes your room dictates the best crossover depending on where your dips are but I think 100Hz 2nd order high pass is a good crossover for most based on minimizing distortion in the LS50 and won't be a problem with sub localization. Don't worry about 100Hz sounding too high, it's actually less attenuation than the 80Hz 4th order slope specified by the THX spec.

 

[Mehdiem]

I'm not familiar with your gear but I've had the same issues for years and the LS50 are a bit harder than most to blend with subs because they want higher crossover frequencies to combat distortion but then you're fighting with a proper blend and subwoofer localization. I've always had dual subs with mine right under the LS50's, using a single sub will be harder to get it right but it's doable. Your Umik and REW will be the best investment you made in your system once you figure out how to take accurate and repeatable measurements, google MMM measurements. Sometimes your room dictates the best crossover depending on where your dips are but I think 100Hz 2nd order high pass is a good crossover for most based on minimizing distortion in the LS50 and won't be a problem with sub localization. Don't worry about 100Hz sounding too high, it's actually less attenuation than the 80Hz 4th order slope specified by the THX spec.

Hey I tried googling MMM measurement, but there are tons of information, I'm so confused. Is there any good resource, or step-by-step guide on how to use REW? I watched a few YouTube videos but there more I watch the more confused I get. The REW website it's not very helpful either. Too much information